The overall objectives of this project are to study the phenomenology, and the biochemical and neuroanatomical substrates of psychomotor stimulant-induced behavioral sensitization. This model is used to study the evolution of behavioral pathology and the role of conditioning or context-dependency in such behaviors. Psychomotor stimulants such as amphetamine and cocaine have been used as pharmacological models of mania, dysphoric mania, and paranoid schizophrenia. Environmental and pharmacological interventions are investigated in an attempt to alter the course of sensitization development and expression. Significant findings to date include demonstration of the following: 1) a novel two day cocaine sensitization paradigm which is context-dependent; 2) the importance of intact dopamine function for the development, but not expression of context-dependent sensitization; 3) a role for the amygdala and nucleus accumbens in this sensitization.